Glad to know that this appears to support my guess to some degree:The neutral density height where the volcanic ash spreads out is called the umbrella region.
Below that is the convective region where there is an upthrust and where particle fallout is determined by their terminal velocity, with larger heavier particles falling out sooner than lighter. Wind will move these particles away from the volcano following the wind direction.
goes into some more detail about the umbrella region and downdrift and fallout of tephra.
I'd love to read more on this topic.The base of the umbrella region (HB) often occurs at the tropopause (boundary between atmosphere and stratosphere) because of temperature inversions.
Pretty spot on I think.Glad to know that this appears to support my guess to some degree:
I'd love to read more on this topic.
In the continental United States, all weather generally moves west to east or northeast, so your observation about the tip of the anvil does not surprise me. Nevertheless, thanks for sharing.What made me think of it was the shape of the classical anvil cloud. In the northern hemisphere, the tip of the anvil usually points East.